Londres De L'ouest.(Translation) . Poem by Michael Walker

You can read the English of this relevant poem on Poem Hunter/ Matthew Arnold/Poems/ 60/63.
The poem is an Italian, or Petrarchan sonnet, with two parts, the octet (first eight lines) , and sestet (last six): and a rhyme scheme: abba/ abba/ cd/ef/ef. The thought break (volta)occurs naturally when he reflects on what he has seen of the little girl begging money from labourers-'Thought I...'. The girl is with her mother and baby sister, dressed in rags.
The girl got some money from working men, after ignoring some rich people, who could have better afforded to be generous. She turned to her own kind, not to a higher social class. The poet thinks that the scene and action point to a better time in the future.
The last point is debatable. Some people have been lifted out of poverty and into work in our time, depending on which country they live in. There is probably less obvious begging in London now than when Arnold wrote the poem. Even so, I encountered much begging in West Auckland, from people who needed money 'for the bus or train' or whatever. It got to be annoying after a while, as it was hard to refuse them.
Although Matthew Arnold came from a privileged background (his father was Headmaster of Rugby School) , he understood the poor, I think.